Coal burner



Aug. 18, 1936. E. c, LILLIE wsmw COAL BURNER Filed Nov. 15, 1934 2 Sheets-Sheet 1 INVENTOR. L ZQW/WV 6'? Z/A/f BY J i ATTORNEY.

E. C. LELLEE COAL BURNER Aug 18 W36 Filed Nov. 13, 1934 2 Sheets-Sheet 2 INVENTOR.

I ATTORNEY.

Patented Aug. 18, 1936 UNITED STATES COAL BURNER Edwin C. Lillie, Wheatridge, 0010., assignor of one-third to Joe Grimes and one-third to Max Meyer, both of Denver, Colo.

Application'November 13, 1934, Serial No. 752,810

I V 6 Claims. (01. 122117) This invention relates to an improved furnace construction and to a process of promoting combustion. The principal object of the invention is to provide a furnace construction for carrying out a process of combustion in which; greater efficienoy will be obtained than with the present constructions; low cost fuels can be efficiently burned; and in which no fusing of the ash can occur to form clinkers.

Another object of the invention is to so construct the furnace that it will automatically feed the fuel to the zone of combustion, and so that the moisture content of the fuel supply will be reduced before the fuel enters the zone of combustion.

A further object of the invention is to so construct the device that a minute and exact control of the secondary air will be possible.

Other objectsand advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efiiciency. These will become more apparent from the'following description.

In the following detailed description of the invention reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawings and throughout the description.

In the drawings:-

Fig. 1 is a vertical section through a typical boiler in which the invention is employed.

F'ig. 2 is a horizontal sectionxtherethrough,

looking downwardly on the line 22 of Fig. 1.

Fig. 3 is a horizontal section looking upwardly on the line 3-3, Fig. l. a

The burner and the boiler may have any desired shape and size suitable to the particular installation in which it is to be used. The boiler illustrated is particularly adaptable to steam or hot water house heating installations and comprises a vertical, cylindrical boiler shell ID, in the bottom of which an ash pit II is formed. Extending upwardly from the ashpit ll through the center of the boiler shell I0, is a cylindrical fuel chamber l2, the lower portion of which forms the firepot of the boiler. The space between the bottom of the fuel chamber and the shell i is closed by means of an annular bottom plate l3. At the top, this space is closed by an annular crown sheet I4.

A series of relatively narrow vertical slots I5 are cut through the lower portion of the wall of the fuel chamber l2 outlining the combustion zone. A fire'tube I6 is positioned back of each of-the slots I5. The tubes l6 lead upwardly and outwardly and terminate through the *crown sheet 4; Thefiretubes it open at their bottoms through the bottom plate l3 to' form secondary air inlets l7. a

An adjustable air control ring 2| is slidably 5 mounted below the secondary air inlets I! so that it may be rotatably reciprocated by means of a suitable handle 22. The ring 2| is slidably supported in 'bracke't members 23 and provided with suitable port openings 24 which, at certain 10 positions of the ring register with the secondary air intakes H.

The bottom of the firepot portion of the chamber I2 is closed by means of any suitable grate l8. At the midportion of the grate I8, an air distributor I9 is positioned. The air distributor extends upwardlya considerable distance at the middle of-- the cha'mber l2 and may have any suitable form. It is preferred to form this distributor as a cylindrical casting preferably provided with a conical top and with a series of vertical air distributing slots 20in its walls.

The boiler'may terminate at the crown sheet I 4 with the fire tubes l6 connecting with any suitable stack. More efiiciency can be obtained, however, by placing one or more heating drums in spaced relation above the crown sheet l4. One such drum is illustrated in Fig. 1 and comprises a water jacket '25 surrounding a central stack passage 29.

An inclined fuel feed hopper extends inwardly and downwardly from the front of the water jacket 25 and-terminates above the fuel chamber l2. This hopper may be provided with a gas trap valve 21, if desired.

A clean out and inspection door '28 is hinged to the boiler shell 10 between the'heating drum and the boiler proper through which fuel may be fed if desired, but primarily for cleanout and inspection purposes. The stack passage 29 may be connected with any suitable stack 30 for carrying away the waste gases.

If just the lower portion of the boilershellis used, the steam or hot water discharges through an outlet 3| and the return water enters through a-feed inlet 32. If the heating drum is employed, the outlet 31 and the inlet 32 are connected by means or one or more vertical pipes 33 which also communicate, at and 35, respectively, with the bottom and top of the water jacket 25. The boiler may of course,be provided with any of the usual accessories such as a water gauge 36, a safety valve'31, and a pressure gauge'38, etc.

"In use, the boiler shell in about the'fuel chamfuel is placed upon the grates [8. The combus-. tion gases can then pass freely upward through portion between'the slots l5 and obtained.

After the fire has become started, the chamber ber l2, and the water jacket 25 are filled with water to the desired level. Fuel is fed into the reservoir 12 through the feed hopper26 so as "to maintain a fuel level substantially as indicated'by the broken line A, Fig. 1. Only the lower portion of this column of fuel, that is the 20, is actually undergoing combustion. The air and combustion gases travel from the vertical slots 20 of the distributor 19 substantially horizontally through the burning fuel to the slots I5, thence upwardly through the fire tubes 16, exiting at the top thereof against the bottom of the water jacket 25, thence to the stack passage 29. If a sufficient depth of bed is maintained in the chamber [2 at all times, very little or no air or gas will travel upwardly through the bed since the pathof least resistance is through the slots [5 and the fire tubes I6.

' At the time of starting the fire, the secondary air-inletsll are preferably olosed by means of the control ring 2| so as to increase the draft through the fire, and a comparatively thin bed of the bed to the stackuntil a hot bed has been I2 is filled substantially to the line A, when it will become impervious to the gases so as to force the'latter into the firetubes IS. The secondary air inlets H can then be opened to supply they meet a in a complete and smokeless combustion within ,andabove the tubes l6. g As the bed burns away, fresh fuel will gradually and continuously settle from the chamber I2. to .take its, placel gradually heated as it descended in the chamber I2 so that it enters the combustion zone at substantiallyan oxidizing temperature. Thus the temperature of the fire .is never lowered as in the usual burner when receiving fresh fuel.

. in heating the boiler. water.

In the usual burner, it is necessaryto heat the moisture content of the fuel substantially to a gasifying or high temperature steaming condition before it escapes from the fire through the stack. This heating of the moisture content to an excessively high temperature, absorbs heat units which could be more effectively employed With this invention, however, the fuel bed above the fire becomes sufficiently heated to drive offthe major portion of the moisture content at a low tem-' perature or vapor from the top of the fuel pile with a comparatively small absorption of heat units. The fuel entering the fire therefore, is practically moistureless, and since the moisture does not enter the fire zone, it is not necessary to raise its temperature to the usual'superheated or steaming condition.

It is desired to call attention to the fact that .in the usual burner a large volume of cold air is necessary in order to support combustion.

This" fresh fuel has been Only a very small proportion of this air is used for oxidizing purposes. The remainder is heated with a wastage of heat units anddischarges simply as hot air through the stack. With the present invention, howevena relatively small volume of air passes through the combustion zone to remove the gases therefrom. These gases are then mixed in a restricted space with a controlled volume of pre-heated air in just sufiicient quantity to support proper combustion.

There is no wastage of heat units in heating unnecessary air. The agitation of the secondary air within the restricted space of the fire tubes prevents stratification and insures the bringing of all of the oxygen content into intimate contact with the combustion gases.

j Thegrates, I8 may have any suitable design capable of efliciently passing the relatively fine ash produced by the burner.

While a specific form of the improvement has been described and illustrated herein, it isdesired to be understood'that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by'Letters Patent 1s: r r r 1. A furnace construction comprising: a cylindrical fuel chamber; a grate closing the bottom of the latter; a water jacket surrounding said chamber; a crown sheet closing the top of said water jacket; a bottom sheet closing the bottom of said water jacket substantially in horizontal alignment with said grate; a series of spacedapart, relatively narrow, vertically positioned, slots through the wall of said chamber adjacent the bottom thereof; fire tubes communicating with and extending upwardly from said slots through said crown sheet; an upwardly extend ing air distributor positioned at the center of said chamber and 40 on the bottom thereof, said distributor having slots positioned horizontally 2. A furnace construction comprising: a cylindrical fuel chamber; awater jacket surrounding slots; and means for introducsaid chamber; a crown sheet closing the top ofsaid water jacket; a bottom sheet closing the bottom of said water jacket; a series of spacedapart, relatively narrow, vertically positioned,

slots through the wall of said chamber adjacent-the bottom thereof; fire tubes communicating with'and extending upwardly from said slots through said crown sheet; anupwardly extending air distributor positioned at the center of said chamber and on the bottom thereof, said distributor having slots positioned horizontally opposite said first slots; means for introducing air into said distributor, said fire tubes opening through said bottom plate below said slots; and means for controlling the openings of said fire tubes through said bottom plate.

3. A furnace construction comprising: a cylindrical fuel chamber; a water jacket surrounding said chamber; a crown sheet closing the top of said water jacket; a bottom sheet closing the bottom of said water jacket; a series of V spaced-apart, relatively narrow, vertically positioned, slots through the wall' of said chamber adjacent the bottom thereof; fire tubes communicating with and extending upwardly from said slots through said crown sheet; an upwardly extending air distributor positioned at the center of said chamber and on the bottom thereof, said distributor having slots positioned horizontally opposite said first slots; and means for introducing air into said distributor, said fire tubes opening through said bottom plate below said slots; an annular plate extending over all of the openings of said firetubes through said bottom plate, said plate being provided with ports; and means for rotating said annular plate to align said ports with said openings.

4. A furnace comprising: a fuel chamber; a grate closing the bottom of said chamber; an ash compartment below said grate; means for feeding fuel into the top of said chamber; a water jacket about said chamber and extending downward thereabout so as to hold water in contact with the wall of said chamber substantially to the level of said grate; a crown sheet closing the top of said jacket; a bottom sheet closing the bottom of said jacket; fire tubes extending between said crown and bottom sheets and opening to said ash compartment, there being vertically positioned slots in the wall of said chamber, each slot communicating with one of said tubes; and an upwardly extending air distributor at the middle of said grate.

5. A furnace comprising: a fuel chamber; a grate closing the bottom of said chamber; an ash compartment below said grate; means for feeding fuel into the top of said chamber; a water jacket about said chamber and extending downward thereabout so as to hold water in contact with the wall of said chamber substantially to the level of said grate; a crown sheet closing the top of said jacket; a bottom sheet closing the bottom of said jacket; fire tubes extending between said crown and bottom sheets and opening to said ash compartment, there being vertically positioned slots in the wall of said chamber, each slot communicating with one of said tubes; and an upwardly extending air distributor at the middle of said grate, said fire tubes contacting the wall of said chamber about said slots and extending outwardly and upwardly so as to be spaced from said wall at said crown sheet.

6. A furnace construction comprising: a vertically positioned fuel chamber; a cylindrical water jacket surrounding said chamber, the inner wall of said jacket forming the wall of said chamber; a grate closing the bottom of said chamber, said wall being provided with verti 'cal slots adjacent said grate; an independent fire tube extending upwardly and outwardly through said water jacket from each of said slots; an air distributor positioned above said grate substantially at the center of said chamber and provided with orifices positioned horizontally opposite the slots in said inner wall, the water in said jacket surrounding said tubes at their point of contact with said inner wall.

EDWIN C. LILLIE. 

